System and method utilizing a conductive brush for providing power signals to a cartridge access device

ABSTRACT

A cartridge access device in a cartridge storage system is designed to retrieve a cartridge from a storage device and to transfer the cartridge to a particular location within the system. Once the cartridge is no longer needed at the particular location, the cartridge access device retrieves the cartridge from the particular location and returns the data cartridge to the storage device. The data cartridge device preferably includes at least two engaging members that engage a respective surface of a frame assembly. Channels in the surfaces of the frame assembly guide the engaging members and, therefore, the cartridge access device as the cartridge access device moves. The engaging members are engaged with a respective conductive track member that extends through the channels in the frame assembly. Electrical current is passed through the conductive track members and the engaging members to the cartridge access device in order to supply the cartridge access device with electrical power and/or to communicate control signals to the cartridge access device. Therefore, a power cable and/or a control cable does not have to be physically connected to the cartridge access device in order for the components on the cartridge access device to receive electrical power and/or control signals.

CROSS REFERENCE TO RELATED APPLICATION(S)

This is a divisional of copending application Ser. No. 09/143,208 filedon Aug. 28, 1998.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates generally to cartridge storage systems forhandling and storing cartridges, such as optical disk or magnetic tapecartridges, and more specifically, to a system and method for supplyingpower and control signals to a movable device (i.e., a cartridge accessdevice) that stores and retrieves cartridges in a cartridge storagesystem.

2. Related Art

Many different types of cartridge storage and handling systems exist andare being used to store data cartridges (and other types of cartridges)at known locations and to retrieve desired cartridges so that data maybe written to and/or read from the data cartridges. Such data storageand handling systems are often referred to as “autochangers” or “jukebox” data storage systems, particularly if they accommodate a largenumber of individual data cartridges.

A typical juke box data storage system includes one or more differenttypes of cartridge-receiving devices for holding the various datacartridges. For example, one type of cartridge-receiving device maycomprise a cartridge storage rack or “magazine” while another type ofcartridge-receiving device may comprise a cartridge read/write device.The cartridge storage racks or magazines serve to provide storagelocations for the data cartridges and are commonly arranged so that theyform one or more vertical stacks. The cartridge read/write device may belocated adjacent the cartridge stack, although the cartridge read/writedevice can be positioned at any convenient location. The data storagesystem may also include a cartridge access device for accessing thevarious data cartridges contained in the cartridge-receiving devices anda positioning device for moving the cartridge access device among thecartridge-receiving devices.

If a host computer system issues a request for data contained on aparticular data cartridge, a control system associated with thecartridge access device actuates the positioning system to move thecartridge access device along the cartridge storage rack until thecartridge access device is positioned adjacent the desired datacartridge. The cartridge access device then removes the data cartridgefrom the cartridge storage rack and carries it to the cartridgeread/write device. The cartridge access device inserts the selected datacartridge into the cartridge read/write device so that the host computermay thereafter read data from or write data to the data cartridge. Afterthe read/write operation is complete, the cartridge access deviceremoves the data cartridge from the read/write device and returns it toa specified location in the cartridge storage rack.

Most cartridge access devices have components that require both powerand control signals. For example, the positioning system that moves thecartridge access device to the appropriate location usually requirespower and control signals in order to appropriately move the cartridgeaccess device.

A simple technique for providing the power and control signals to thecartridge access device is to connect a power cable and a control cableto the cartridge access device, as is commonly done in the prior art.The power cable supplies the components of the cartridge access devicewith power, and the control cable provides the cartridge access devicewith control signals for proper operation. Both the power cable and thecontrol cable can be tied together or integrated into a single cable.

However, if the cables are not properly secured, the cables caninterfere with the motion of the cartridge access device. For example,the cables can block the path of movement of the cartridge access devicecausing the cartridge access device to malfunction or jam.Alternatively, the cables can wrap around the cartridge access device asthe cartridge access device moves in different directions, therebyimpeding the motion of the cartridge access device or interfering withthe retrieval of the data cartridge.

Furthermore, having a cable coupled to the moving cartridge accessdevice can make it more difficult to manufacture and service the datastorage system. In this regard, the cable can interfere with efforts toinstall, remove, and access the cartridge access device and othercomponents in the system. In addition, communicating signals through thecable can adversely emit radio frequency interference (RIF) from thecable. Other problems associated with having a cable coupled to a movingcartridge access device should be apparent to one ordinarily skilled inthe art.

Thus, a heretofore unaddressed need exists in the industry for a systemand method of providing power and/or control signals to a movablecartridge access device within a data storage system without disruptingthe motion of the cartridge access device.

SUMMARY OF THE INVENTION

The present invention overcomes the inadequacies and deficiencies of theprior art as discussed herein. Generally described, the presentinvention provides a system and method for providing power and controlsignals to a movable device that retrieves and stores cartridges withina cartridge storage system without connecting a power cable to themovable device.

The present invention utilizes a frame assembly, an engaging member, aconductive member, and a cartridge access device. The frame assembly hasa channel or groove. The conductive member is attached to a surface ofthe frame assembly and extends through the channel of the frameassembly. The cartridge access device receives and transports cartridgesfrom one location within the cartridge storage system to anotherlocation within the cartridge storage system. The first engaging memberis coupled to the cartridge access device and engaged with theconductive member. The engaging member is conductive so that electricalsignals can be passed between the engaging member and the conductivemember attached to the frame assembly.

In accordance with another feature of the present invention, theengaging member includes a shaft, a brush, a rod, and a spring. Thebrush is coupled to the rod which is inserted into a hole in the shaft.The spring is coupled to the rod and engaged with the shaft so that aforce generated by the spring tends to push the brush away from theshaft and toward the conductive member. Due to the force generated bythe spring, the brush engages the conductive member and maintainscontact with the engaging member (i.e., slides across a surface of theengaging member) as the cartridge access device moves.

In accordance with another feature of the present invention, controlsignals are superimposed on a power signal that is supplied to thecartridge access device via the conductive member and the engagingmember. A filter is designed to filter out the power signal from thecontrol signals so that the control signals can be recovered andutilized by the cartridge access device in order to operate thecomponents of the cartridge access device.

The present invention can also be viewed as providing a method fortransferring data cartridges within a data storage system. Brieflydescribed, the method can be broadly conceptualized by the followingsteps: inserting a cartridge associated with the cartridge storagesystem into a cartridge access device; moving the cartridge accessdevice; sliding a brush coupled to the cartridge access device across asurface of the conductive member during the moving step; and supplyingthe cartridge access device with electrical power via the brush and theconductive member.

The present invention has many advantages, a few of which are delineatedhereafter, as mere examples.

An advantage of the present invention is that electrical power can besupplied to components of a cartridge access device within a datastorage system without connecting a power cable to the cartridge accessdevice.

Another advantage of the present invention is that control signals canbe supplied to the cartridge access device without connecting a controlcable to the cartridge access device.

Another advantage of the present invention is that the cartridge accessdevice can move through the data storage system without interferencefrom a power cable or a control cable.

Another advantage of the present invention is that radio frequencyinterference (RIF) associated with a cartridge storage system can bereduced.

Another advantage of the present invention is that the cartridge accessdevice with the cartridge storage system can be easier to access and toinstall.

Other features and advantages of the present invention will becomeapparent to one skilled in the art upon examination of the followingdetailed description, when read in conjunction with the accompanyingdrawings. It is intended that all such features and advantages beincluded herein within the scope of the present invention, as is definedby the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdrawings. The elements of the drawings are not necessarily to scalerelative to each other, emphasis instead being placed upon clearlyillustrating the principles of the invention. Furthermore, likereference numerals designate corresponding parts throughout the severalviews.

FIG. 1 is a top view of a cartridge storage system according to thepresent invention showing a cartridge access device in variouspositions;

FIG. 2 is a three-dimensional side view of a frame assembly that may beused to house the cartridge access device depicted in FIG. 1;

FIG. 3 is a side view of the frame assembly depicted in FIG. 2;

FIG. 4 is a three-dimensional side view of the cartridge access devicedepicted in FIG. 1;

FIG. 5 is an enlarged side view of an actuator system and lower bearingand wheel assembly of the cartridge access device depicted in FIG. 1;

FIG. 6 is an enlarged end view of the actuator system and lower bearingand wheel assembly of FIG. 5;

FIG. 7 is a block diagram illustrating a host computer system that mayuse the cartridge storage system of FIG. 1 to retrieve and store datacartridges;

FIG. 8 is a block diagram illustrating a computer system for controllingthe cartridge access device of FIG. 1;

FIG. 9 is a top view of a lower plate of the frame assembly of FIG. 2;

FIG. 10 is a three-dimensional side view of the cartridge access deviceof FIG. 4 coupled to power tracks that supply electrical power andcontrol signals to the cartridge access device;

FIG. 11A is a three-dimensional side view of an engaging member that iscoupled to the cartridge access device and engages the power tracks ofFIG. 10;

FIG. 11B is a three-dimensional side view of the engaging member of FIG.11A once the engaging member is inserted into a shaft;

FIG. 12 is a three dimensional side view of a conical device and anoptical communications device used by the cartridge access device ofFIG. 4 to communicate with the computer system of FIG. 7;

FIG. 13 is a three-dimensional side view of the optical communicationsdevice and conical device of FIG. 12 illustrating optical light beingreflected into the optical communications device;

FIG. 14A is a side view of the conical device of FIG. 13; and

FIG. 14B is a top view of the conical device of FIG. 14A.

DETAILED DESCRIPTION OF THE INVENTION

A cartridge storage system 10 according to the present invention isshown in FIG. 1 and may include a cartridge handling system 12 fortransferring cartridges 14 between one or more cartridge-receivingdevices, such as one or more cartridge storage racks or magazines 16 andone or more cartridge read/write devices 18. Although different types ofcartridges 14 are possible, the present invention will be described forillustrative purposes where the cartridges 14 are data cartridges.However, the term “cartridge” is not limited to data cartridges and isdefined as a movable unit of equipment designed to fit into a largerpiece of equipment. For example, the cartridges 14 can comprise a vileof fluid to be transported in a testing laboratory.

Although other configurations are possible, the variouscartridge-receiving devices (e.g., the cartridge storage racks ormagazines 16 and the cartridge read/write devices 18) may be positionedat various locations around the cartridge handling system 12 so thatthey define the generally U-shaped configuration shown in FIG. 1.Accordingly, the cartridges 14 may be accessed from three (3) cartridgeaccess planes 41,43, and 45.

The cartridge handling system 12 is shown in more detail in FIG. 2 andmay comprise a frame assembly 26 which includes a lower or base plate 28and an upper or top plate 30 that are held in generally parallel,spaced-apart relation by a support structure 47. The frame assembly 26of the cartridge handling system 12 may define a first cartridge accessside 20, a second cartridge access side 22, and a third cartridge accessside 24. The first and third cartridge access sides 20 and 24 may bepositioned in generally spaced-apart relation, whereas the secondcartridge access side 22 may be oriented generally transverse to thefirst and third cartridge access sides 20 and 24. The variouscartridge-receiving devices may be positioned around the cartridgehandling system 12 so that the cartridge access planes 41, 43, and 45(FIG. 1) defined by the cartridge-receiving devices are located adjacentthe three cartridge access sides 20, 22, and 24.

The lower plate 28 of frame assembly 26 may include a lower U-shapedguide member or channel 32 that forms a substantially continuous memberalong the first, second, and third cartridge access sides 20, 22, and 24of the frame assembly 26. Similarly, the upper plate 30 may include anupper U-shaped guide member or channel 34 (FIG. 3) that also forms asubstantially continuous member along the first, second, and thirdcartridge access sides 20, 22, and 24 of the frame assembly 26.

The cartridge handling system 12 (FIG. 2) may also include a cartridgeaccess device 36 (FIG. 4) capable of loading and retrieving thecartridges 14 (FIG. 1) from the cartridge-receiving devices (e.g.,cartridge storage racks 16 and the cartridge read/write devices 18). Thecartridge access device 36 engages the upper and lower U-shaped guidemembers or channels 32 and 34 in the respective lower and upper plates28 and 30, and is thus guided by the lower and upper guide members 32and 34 along the first, second, and third cartridge access sides 20, 22,and 24. That is, the cartridge access device 36 moves along a generallyU-shaped path 40 (FIG. 1). For example, the cartridge access device 36may be moved between a first position 38 adjacent the first access side20 of frame assembly 26, a second position 38′ adjacent the secondaccess side 22, and a third position 38″ adjacent the third access side24, as seen in FIG. 1. The cartridge access device 36 may also be movedfrom a position adjacent the third cartridge access side 24 to positionsadjacent either the second cartridge access side 22 or the firstcartridge access side 20.

Although other actuation systems are possible, the cartridge accessdevice 36 is preferably moved along the lower and upper guide members 32and 34 (i.e., following the U-shaped path 40) by an actuator system 42,as depicted in FIGS. 5 and 6. In one preferred embodiment, the actuatorsystem 42 may comprise a rack and pinion drive system having asubstantially continuous lower gear rack 44 provided on the lower plate28 at a position adjacent the lower U-shaped guide member or channel 32.Accordingly, the lower gear rack 44 defines a substantially continuous,U-shaped member. An upper gear rack 46 (FIG. 3) may be provided on theupper plate 30 at a position adjacent the upper U-shaped guide member orchannel 34. The upper gear rack 46 (FIG. 3) also defines a substantiallycontinuous, U-shaped member. Lower and upper drive pinions 48 and 50(FIG. 4) mounted to the cartridge access device 36 engage the respectivelower and upper gear racks 44 and 46. A pinion drive assembly 52 mountedto the cartridge access device 36 rotates the lower and upper piniongears 48 and 50, thereby moving the cartridge access device 36 back andforth along the lower and upper guide members 32 and 34, following theU-shaped path 40. See FIG. 1.

In operation, the cartridge storage system 10 according to the presentinvention may be used to transfer a plurality of cartridges 14 betweenthe various cartridge-receiving devices (e.g., cartridge storage racksor magazines 16 and the cartridge read/write devices 18) positionedadjacent the first, second, and third cartridge access sides 20, 22, and24. Therefore, the cartridge storage system 10 may be used by a computersystem 53 (FIG. 7), for example, or other data processing system tostore and access data contained in the cartridges 14.

In this regard, the computer system 53 preferably includes control logic54 that determines when data should be stored on or read from aparticular cartridge 14. The control logic 54 of the computer system 53can be implemented in software, hardware, or a combination thereof. Inthe preferred embodiment, as illustrated by way of example in FIG. 7,the control logic 54 of the present invention along with its associatedmethodology is implemented in software and stored in computer memory 55of the computer system 53. Note that the control logic 54 can be storedand transported on any computer-readable medium for use by or inconnection with a computer-readable system or method. In the context ofthis document, a computer-readable medium is an electronic, magnetic,optical, or other physical device or means that can contain or store acomputer program for use by or in connection with a computer-relatedsystem or method. As an example, the control logic 54 may bemagnetically stored and transported on a conventional portable computerdiskette.

The preferred embodiment of the computer system 53 of FIG. 7 comprisesone or more conventional processing elements 59, such as a digitalsignal processor (DSP), that communicate to and drive the other elementswithin the system 53 via a local interface 61, which can include one ormore buses. Furthermore, an input device 63, for example, a keyboard ora mouse, can be used to input data from a user of the system 53, andscreen display 65 or a printer 67 can be used to output data to theuser. A disk storage mechanism 69 can be connected to the localinterface 61 to transfer data to and from a nonvolatile disk (e.g.,magnetic, optical, etc.). The system 53 can be connected to a networkinterface 71 that allows the system 53 to exchange data with a network74.

The computer system 53 also preferably includes a communications device77′ (FIGS. 1 and 7) coupled to the system 53 via any suitable interface78. The communications device 77′ communicates wireless signals with thecartridge access device 36. If the control logic 54 determines that aparticular cartridge 14 should be retrieved, the control logic 54 viacommunications device 77′ issues a request for data to the cartridgeaccess device 36.

In the preferred embodiment the wireless signals are optical signals(e.g., infrared signals) and the communications device 77′ (and opticalcommunications device 77″, as discussed later) are opticalcommunications devices. However, other types of wireless signals can becommunicated between communications devices 77′ and 77″, in which thecommunications devices 77′ and 77″ should be configured to be compatiblewith the types of signals being communicated. Since the signals areoptical in the preferred embodiment, communications devices 77′ and 77″will be discussed hereinafter as “optical” communications devices 77′and 77″, for illustrative purposes. However, one skilled in the artshould realize that communications devices 77′ and 77″ should becompatible with the type of wireless signals being communicated in thepresent invention.

A control system 81 (FIG. 8) associated with the cartridge access device36 controls the actuator system 42 (FIGS. 5 and 6) on the cartridgeaccess device 36 as necessary to move the cartridge access device 36along the U-shaped path 40 until the cartridge access device 36 islocated adjacent the appropriate cartridge 14. The control system 81 ofthe present invention can be implemented in software, hardware, or acombination thereof. In the preferred embodiment, as illustrated by wayof example in FIG. 8, the control system 81 of the present inventionalong with its associated methodology is implemented in software andstored in computer memory 83 of a computer system 85. The computersystem 85 is preferably located on the cartridge access device 36. Notethat the control system 81 can be stored and transported on anycomputer-readable medium for use by or in connection with acomputer-readable system or method.

The preferred embodiment of the computer system 85 of FIG. 8 comprisesone or more conventional processing elements 86, such as a digitalsignal processor (DSP), that communicate to and drive the other elementswithin the system 85 via a local interface 87, which can include one ormore buses. Furthermore, the system 85 preferably includes an opticalcommunications device 77″ for communicating optical signals with theoptical communications device 77′ of the computer 53. The opticalcommunications device 77″ is coupled to the system 85 via any suitableinterface 88.

Consider, for example, an initial condition wherein the desiredcartridge 14 is stored in one of the cartridge storage racks ormagazines 16 (FIG. 1). Upon receiving a request for the cartridge 14from the computer system 53 (FIG. 7), the control system 81 (FIG. 8) ofthe cartridge access device 36 (FIG. 4) operates the actuator system 42(FIGS. 5 and 6) to move the cartridge access device 36 along theU-shaped path 40 (FIG. 1) until the cartridge access device 36 isadjacent the selected cartridge 14 in the storage rack 16. A cartridgeengaging device or “picker” (not shown) associated with the cartridgeaccess device 36 then engages the cartridge 14 and draws it into thecartridge access device 36, as depicted by FIG. 4. The actuator system42 then actuates the pinion drive assembly 52 as necessary to move thecartridge access device 36 to a desired cartridge read/write device 18(FIG. 1). Once properly positioned adjacent the desired cartridgeread/write device 18, the cartridge engaging assembly or picker (notshown) associated with the cartridge access device 36 loads thecartridge 14 into the cartridge read/write device 18. The computersystem 53 (FIG. 7) is configured to have access to the data on thecartridge 14 once the cartridge 14 is loaded into the cartridgeread/write device 18.

When the cartridge 14 is no longer needed, the control system 81 (FIG.8) may operate the actuator system 42 (FIGS. 5 and 6) to move thecartridge access device 36 (FIG. 1) along the U-shaped path 40 until thecartridge access device 36 is again located at a position adjacent thecartridge read/write device 18 (assuming the cartridge access device 36is not already located in the appropriate position). Thereafter, thecartridge engaging assembly or picker (not shown) may retrieve thecartridge 14 from the cartridge read/write device 18. The cartridgeaccess device 36 may then return the cartridge 14 to its appropriatelocation in the cartridge storage racks or magazines 16.

Having briefly described the cartridge storage system 10 according tothe present invention, the various embodiments of the cartridge storagesystem 10 will now be described in detail. However, before proceedingwith the detailed description, it should be noted that while thecartridge storage system 10 is shown and described herein as it could beused to store and retrieve magnetic cartridges 14 having a certain sizeand configuration (e.g., DLT or digital linear tape cartridges), it isnot limited to any particular type of data cartridge. Indeed, thecartridge storage system 10 according to the present invention can beused with any type of data storage device comprising any type of datastorage medium (e.g., magnetic disk or tape, optical disk, etc.).Consequently, the present invention should not be regarded as limited touse with the particular type and style of cartridge 14 shown anddescribed herein.

Referring back to FIG. 1, one embodiment of the cartridge storage system10 according to the present invention may comprise a main housing orchassis 154 configured to hold the various components of the cartridgestorage system 10. For example, in one preferred embodiment, the mainhousing or chassis 154 may comprise a generally rectangularly shapedstructure adapted to receive the cartridge handling system 12, one ormore cartridge-receiving devices, such as one or more cartridge storageracks or magazines 16 and one or more cartridge read/write devices 18.The housing or chassis 154 may also be adapted to receive any of a widerange of other components or devices (e.g., control systems, powersupplies, etc.) well-known in the art and that may be required ordesired for the operation of the cartridge storage system 10. Thehousing or chassis 154 may also be provided a cartridge magazine accessend 156 to allow a user to access the cartridge storage racks ormagazines 16. An access door (not shown) may be provided on the accessend 156 to provide access to the cartridge magazines 16. Although notrequired, the housing or chassis 154 is preferably sized to be receivedby a standard storage rack system (not shown), such as an EIA rackassembly available from Crenlo Corp. of Minnesota (USA).

In one preferred embodiment, the cartridge handling system 12 maycomprise a generally rectangularly shaped structure having a firstcartridge access side 20, a second cartridge access side 22, and a thirdcartridge access side 24. As used herein, the term “cartridge accessside” refers to any side of the cartridge handling system 12 from whichcartridges 14 may be accessed, either from a cartridge storage rack ormagazine 16 or a cartridge read/write device 18.

The cartridge handling system 12 defines the general arrangement of thecartridge access planes associated with the cartridge-receiving devices(e.g., the cartridge storage racks or magazines 16 and the cartridgeread/write devices 18). That is, the cartridge-receiving devices shouldbe arranged around the cartridge handling system 12 so that thecartridge access planes defined by the cartridge-receiving devices arelocated at positions adjacent the cartridge access sides of thecartridge handling system 12. For example, in one preferred embodiment,the various cartridge-receiving devices (e.g., the cartridge storageracks or magazines 16 and cartridge read/write devices 18) are arrangedaround the cartridge handling system 12 so that first cartridge accessplane 41 is positioned adjacent the first cartridge access side 20, thesecond cartridge access plane 43 is positioned adjacent the secondcartridge access side 22, and the third cartridge access plane 45 ispositioned adjacent the third cartridge access side 24.

In accordance with the forgoing considerations, the variouscartridge-receiving devices (e.g., the cartridge storage racks ormagazines 16 and the cartridge read/write devices 18) may be locatedadjacent any cartridge access side (e.g., 20, 22, and 24) of thecartridge handling system 12 in any of a variety of arrangements. Forexample, in one preferred embodiment, two cartridge storage racks ormagazines 16 are located adjacent the first cartridge access side 20 ofthe cartridge handling system 12, whereas another pair of magazines 16are located adjacent the third cartridge access side 24. A pair ofcartridge read/write devices or “drives” 18 are located adjacent thesecond cartridge access side 22 of the cartridge handling system 12.Alternatively, a different number of cartridge storage racks 16 could beprovided, or the cartridge read/write devices 18 could be locatedadjacent either or both of the first or third cartridge access sides 20and 24.

The U-shaped arrangement of the cartridge storage magazines 16 andcartridge read/write devices 18 just described and shown in FIG. 1 forthe preferred embodiment allows the various cartridge storage racks ormagazines 16 to be easily accessed by a user from the cartridge accessend 156 of the chassis or housing assembly 154. That is, the user mayreplace the various magazines 16 from time to time to provide differentcartridges 14 to the cartridge storage system 10. Alternatively, thevarious cartridge storage racks or magazines 16 and cartridge read/writedevices 18 could be configured around the cartridge handling system 12in any other convenient arrangement depending on the requirements of theparticular application.

Referring to FIG. 2, the cartridge handling system 12 preferablycomprises a generally rectangular structure or frame assembly 26 thatincludes a lower or base plate 28, an upper or top plate 30, and asupport structure 47. The support structure 47 holds or positions thelower plate 28 and upper plate 30 in generally parallel, spaced-apartrelation. The frame assembly 26 defines a first cartridge access side20, a second cartridge access side 22, and a third cartridge access side24. The first and third cartridge access sides 20 and 24 are positionedin spaced-apart relation, whereas the second cartridge access side 22 ispositioned generally transverse to the first and third cartridge accesssides 20 and 24. Accordingly, the three cartridge access sides 20, 22,and 24 define a generally U-shaped configuration about which the variouscartridge magazines 16 and read/write devices 18 may be arranged. SeeFIG. 1. Alternatively, however, the various cartridge access sides 20,22, and 24 can be arranged in other configurations.

For example, instead of being positioned at substantially right anglesto one another, the various cartridge access sides 20, 22, and 24 couldbe positioned so that they form oblique (i.e., non-perpendicular) angleswith respect to one another, such as would be the case if the frameassembly 26 comprised a pentagonal (5-sided) or hexagonal (6-sided)configuration. In still another alternative, the cartridge access sides20, 22, and 24 need not comprise straight segments, but could insteadcomprise curvilinear segments or portions, such as may be the case ifthe frame assembly 26 were provided with a circular or semi-circularcross-section. Consequently, the present invention should not beregarded as limited to a frame assembly 26 having cartridge access sides20, 22, and 24 arranged according to the geometrical configurationsshown and described herein.

Referring to FIGS. 3 and 9, the lower plate 28 may comprise aplate-like, generally rectangular member that includes a lower guidemember or channel 32 therein. The lower guide member or channel 32 maycomprise a first elongate section 158 located adjacent the firstcartridge access side 20 and a second elongate section 160 locatedadjacent the second cartridge access side 22. The lower guide member orchannel 32 may also include a third elongate section 162 that is locatedadjacent the third cartridge access side 24. The second elongate section160 is joined to the first and third elongate sections 158 and 162 byrespective rounded corner sections 164 and 166. Accordingly, the first,second, and third elongate sections 158, 160, and 162 define asubstantially continuous guide member 32 that extends along the threecartridge access sides 20, 22, and 24 of the cartridge handling system12.

The upper plate 30 is essentially identical to the lower plate 28 justdescribed and may comprise a plate-like, generally rectangular memberhaving an upper U-shaped guide member or channel 34 therein. The upperU-shaped guide member 34 may include first and third elongate sections168 and 170 that are located adjacent the respective first and thirdcartridge access ends 20 and 24. See FIG. 3. The upper guide member orchannel 34 may also include a second elongate section (not shown)located adjacent the second cartridge access side 22. The secondelongate section (not shown) of the upper guide member or channel 34 isconnected to the first and third elongate sections 168 and 170 byrespective rounded corner sections (not shown) in a manner essentiallyidentical to those of the lower guide member 32 in the lower plate 28.

The lower and upper plates 28 and 30 may be made from any of a widerange of materials, such as metals or plastics, suitable for theintended application. By way of example, in the preferred embodiment,the lower and upper plates 28 and 30 are molded as single pieces from apolycarbonate plastic material, although other materials could also beused. The lower and upper guide members or channels 32 and 34 formedwithin the lower and upper plates 28 and 30 may have any of a wide rangeof widths and depths suitable for the intended application. In thepreferred embodiment, both lower and upper guide channels 32 and 34 havewidths of about 7.16 mm and depths of about 6.0 mm.

The support structure 47 for holding the lower and upper plates 28 and30 in essentially parallel, spaced-apart relation may be made from anyof a wide range of materials, such as metals or plastics, suitable forthe intended application. In the preferred embodiment, the supportstructure 47 is fabricated from sheet metal and is secured to the lowerand upper plates 28 and 30 by any convenient fastener system or device(e.g., screws).

Referring to FIG. 4, the cartridge access device 36 may comprise astructure sized to receive the cartridges 14 (FIG. 1) used in thecartridge storage system 10. The cartridge access device 36 may also beprovided with a cartridge engaging assembly or “picker” (not shown)suitable for loading and retrieving the cartridges 14 to and from theparticular cartridge-receiving device (e.g., cartridge storage rack 16or cartridge read/write device 18) in which the cartridge 14 is held.Examples of cartridge engaging assemblies or “pickers” suitable for usein the present invention are disclosed in the following U.S. patentswhich are specifically incorporated herein by reference: U.S. Pat. No.4,998,232 entitled “Optical Disk Handling Apparatus with Flip Latch;”U.S. Pat. No. 5,010,536 entitled “Cartridge Handling System;” U.S. Pat.No. 5,014,255 entitled “Optical Disk Cartridge Handling Apparatus withPassive Cartridge Engagement Assembly;” and U.S. Pat. No. 5,043,962entitled “Cartridge Handling System.” Alternatively, any of a wide rangeof other types of cartridge engaging assemblies or pickers that arewell-known in the art also may be used in the present invention. In anyevent, since such cartridge engaging assemblies or “pickers” arewell-known in the art and are not necessary in understanding the presentinvention, the particular cartridge engaging assembly utilized will notbe described in further detail.

Regardless of the particular type of style of cartridge engagingassembly or “picker” that is utilized in the cartridge access device 36,the cartridge access device 36 may be mounted to the lower and upperU-shaped guide members 32 and 34 so that the cartridge access device 36may be moved along the first, second and third cartridge access sides20, 22, and 24 generally following the U-shaped path 40. See FIG. 1.More specifically, the cartridge access device 36 may be retained in thelower U-shaped guide member or channel 32 by a pair of lower engagingmembers 174 and 176 that extend from the bottom of the cartridge accessdevice 36. In one preferred embodiment, the lower engaging member 174may be attached to a shaft 182 that may be mounted to the cartridgeaccess device 36. Alternatively, other mounting arrangements could beused to attach the lower engaging member 174 to the cartridge accessdevice 36, as would be obvious to persons having ordinary skill in theart. The lower engaging member 176 may be attached to the end of thelower pinion 48, in the manner depicted by FIG. 4, or may even comprisean integral portion of the lower pinion 48.

The top of the cartridge access device 36 may be provided with a pair ofupper engaging members 186 and 188 that are sized to be slidablyreceived in the upper U-shaped guide member or channel 34. The upperengaging member 186 may be mounted to the top of the cartridge accessdevice 36. The upper engaging member 188 may be mounted to the end ofthe upper pinion 50, or may even comprise an integral portion of theupper pinion 50. The lower and upper engaging members 174, 176, 186, and188 guide the cartridge access device 36 along the lower and upper guidemembers 32 and 34 associated with the lower and upper plates 28 and 30.Finally, the bottom of the cartridge access device 36 may be providedwith a guide wheel 190 (FIGS. 5 and 6) which contacts the lower plate 28and supports the weight of the cartridge access device 36. Optionally,the distal end 192 of the cartridge access device 36 also may beprovided with a similar wheel arrangement (not shown) to support thedistal end 192 of the cartridge access device 36.

Except as described hereinafter, the lower and upper engaging members174, 176, 186, and 188 may be made from any of a wide range ofmaterials, such as metals or plastics (e.g., copper, brass or nylon),suitable for providing a low friction engagement with the respectivelower and upper guide members or channels 32 and 34 in the respectivelower and upper plates 28 and 30. In the preferred embodiment, the lowerand upper engaging members 174, 176, 186, and 188 have diameters ofabout 7.01 mm which provides 0.15 mm of clearance between the engagingmembers and the guide channels, which, as mentioned above, have widthsof about 7.16 mm.

In order to eliminate the need to attach a power cable to the cartridgeaccess device 36, at least one of the lower engaging members 174 and 176and at least one of the upper engaging members 186 and 188 form a brushcapable of providing electrical power to the cartridge access device 36.In this regard, the lower engaging members 174 and 176 and the upperengaging members 186 and 188 are preferably engaged with power tracks201 and 203, respectively, as depicted by FIG. 10. The power tracks 201and 203 are preferably attached to the lower and upper plates 28 and 30in channels 32 and 30, respectively, as depicted by FIGS. 3, 9, and 10.The power tracks 201 and 203 are preferably comprised of a conductivematerial, such as copper for example. Each power track 201 and 203 ispreferably a continuous member attached to and extending along a surfaceof the lower and upper plates 28 and 30 within the channel 32 and 34,respectively. However, it is possible that the power tracks 201 and 203may be located outside of the channels 32 and 34, if desired. The powertracks 201 and 203 are located within the channels 32 and 34 in thepreferred embodiment in order for the engaging members 174 and 186(which are coupled to the power tracks 201 and 203, respectively) tohelp guide the cartridge access device 36 around the U-shaped path 40.

For illustrative purposes, assume that engaging members 174 and 186 areconfigured to provide power to the cartridge access device 36. Referringto FIG. 11A, each engaging member 174 and 186 includes a brush 204coupled to a rod 205. The brush 204 is preferably cylindrical in orderto facilitate movement of the brush 204 through the channel 32 or 34,especially at the corners of the channels 32 or 34. The brush 204 ispreferably comprised of a conductive material in order for the engagingmember 174 or 186 to pass electrical power received from the power track201 or 203, respectively, to other components in the access cartridgedevice 36. Furthermore, since the brush 204 engages the power track 201or 203 as the cartridge access device 36 moves around the U-shaped path40, the brush 204 is preferably comprised of a durable material having alow coefficient of friction on the surface.

The rod 205 is preferably coupled to a spring 207. The engaging member174 or 186 is then inserted into shaft 182, as depicted by FIG. 11B.Preferably, the shaft includes two sections, a larger portion 182′ and asmaller portion 182″, each portion 182′ and 182″ having a hole or othertype of hollow region. The hole of the larger portion 182′ preferablyhas a diameter or width larger than the diameter or width of the spring207, and the hole of the smaller portion 182″ preferably has a diameteror width smaller than the diameter or width of the spring 207.Furthermore, the engaging member 174 or 186 is preferably inserted intothe larger portion 182′ of the shaft before being inserted into thesmaller portion 182″ (i.e., the rod 205 is inserted into the largerportion 182′ first), and the rod 205 is preferably inserted into theshaft 182 first (i.e., the rod 205 is inserted into the shaft 182 beforethe brush 204).

Therefore, when the engaging member 174 or 186 is inserted into theshaft 182 the spring 207 engages the smaller portion 182″ of the shaft182 and is compressed as the engaging member 174 or 186 is insertedfurther into the shaft 182. Consequently, the spring 207 generates aforce on the brush 204 and rod 205 that tends to push the brush 204 awayfrom the shaft 182. As a result, when the engaging members 174 and 186are engaged with the power tracks 201 and 103, respectively, as depictedby FIG. 10, the force generated by the spring 207 tends to push thebrush 204 against the power track 201 or 203. Moreover, as the cartridgeaccess device 36 moves around the U-shaped path 40, the force generatedby the spring 207 ensures that the brush 204 is engaged with the powertrack 201 or 203.

The rod 205 is preferably comprised of a conductive material in order toallow electrical current to flow through the rod 205. Although othermaterials are possible, the rod 205 is preferably comprised of brass,since brass is conductive and resistant to fatigue that may be caused bythe forces generated on the rod 205 as the cartridge access device 36moves along the U-shaped path 40.

Preferably, a voltage potential exists between the power tracks 201 and203. For example, the power track 201 can be configured to maintain aground voltage, while the power track 203 can be configured to maintaina power voltage (i.e., a voltage different than the ground voltage) orvice versa. Therefore, in the example where the power track 201maintains the ground voltage, the brush 204 and rod 205 of the upperengaging member 186 supplies the power voltage to the cartridge accessdevice 36, and the brush 204 and rod 205 of the lower engaging member174 supplies the ground voltage to the cartridge access device 36. Inthis regard, power wires can be connected to the rods 205 of the upperand lower engaging members 174 and 186, which carry the power to othercomponents in the cartridge access device 36 through techniques known inthe art. Since the upper and lower engaging members 174 and 186 providethe electrical power to the cartridge access device 36, a power cabledoes not need to be attached to the cartridge access device 36 in orderto provide power to the components of the cartridge access device 36.Instead, a connection or terminal having one voltage should be connectedto power track 201, and another connection or terminal having anothervoltage should be connected to power track 203.

As described above, the cartridge access device 36 is moved along thelower and upper guide members 32 and 34 by an actuator system 42 (FIGS.5 and 6). In the preferred embodiment, the actuator system 42 maycomprise a rack and pinion drive system having a substantiallycontinuous lower gear rack 44 provided on the lower plate 28 at aposition adjacent the lower U-shaped guide member or channel 32.Similarly, a substantially continuous upper gear rack 46 (FIG. 3) may beprovided on the upper plate 30 at a position adjacent the upper U-shapedguide member or channel 34. Lower and upper drive pinions 48 and 50(FIGS. 4-6) mounted to the cartridge access device 36 engage therespective lower and upper gear racks 44 and 46. The pinion driveassembly 52 mounted to the cartridge access device 36 rotates the lowerand upper pinion gears 48 and 50 to move the cartridge access device 36back and fourth along the U-shaped path 40 (FIG. 1).

Referring now specifically to FIGS. 3 and 9, the lower gear rack 44 maycomprise first and second elongate sections 192 and 194 that areprovided on the lower plate 28 adjacent the first and second elongatesections 158 and 160 of the lower guide member or channel 32. A thirdelongate section 196 may be provided on the lower plate 28 at a positionadjacent the third elongate section 162 of lower guide member 32. Thesecond elongate section 194 of lower gear rack 44 may be joined to thefirst and third elongate sections 192 and 196 of lower gear rack 44 byrespective rounded corner sections 197 and 198. The lower gear rack 44may therefore comprise a substantially continuous, U-shaped member thatextends along substantially the entirety of the lower U-shaped guidemember or channel 32.

The upper gear rack 46 is essentially identical to the lower gear rack44 just described and may include first and third elongate sections 191and 195 that are provided on the upper plate 30 at positions adjacentthe respective first and third elongate sections 168 and 170 of theupper guide member or channel 34. A second elongate section 93 may beprovided on the upper plate 30 at a position adjacent the secondelongate section (not shown) of upper guide member 34. The secondelongate section 93 of upper gear rack 46 may be connected to the firstand third elongate sections 191 and 195 of upper gear rack 46 byrespective rounded corner sections 189 and 199. The upper gear rack 46may therefore comprise a substantially continuous, U-shaped member thatextends along substantially the entirety of the upper U-shaped guidemember or channel 34.

The lower and upper gear racks 44 and 46 may be made from any of a widevariety of materials, such as metals or plastics, suitable for theintended application. By way of example, in one preferred embodimentwherein the lower and upper plates 28 and 30 are molded from apolycarbonate plastic material, the lower and upper gear racks 44 and 46are provided as integrally molded portions of the lower and upper plates28 and 30 (i.e., the lower and upper gear racks 44 and 46 comprise thepolycarbonate plastic material). Alternatively, the lower and upper gearracks 44 and 46 may comprise separate components that are then fixedlyattached to the lower and upper plates 28 and 30 by any of a wide rangeof fastening systems or devices (e.g., adhesives, screws, rivets, etc.).

The lower and upper gear racks 44 and 46 may be provided with anyconvenient tooth pitch suitable for the intended application. In onepreferred embodiment, the lower and upper gear racks 44 and 46 may havea tooth pitch of about 32, although other tooth pitches may also beused.

Referring now to FIGS. 3-6, the cartridge access device 36 may beprovided with lower and upper pinion gears 48 and 50 which engage thelower and upper gear racks 44 and 46, respectively. The lower and upperpinion gears 48 and 50 may be mounted to a drive shaft 15 which may bejournalled for rotation in the cartridge access device 36. Therefore, asthe drive shaft 15 is rotated by the pinion drive assembly 52, the lowerand upper pinion gears 48 and 50 are rotated, thereby moving thecartridge access device 36.

The pinion drive assembly 52 may comprise a motor 25 and a reductiongear assembly 27 mounted within gearbox housing 23. The reduction gearassembly 27 may comprise one or more spur gears for reducing the speedof the motor 25. The drive shaft 15 may be operatively connected to theoutput pinion 29 of reduction gear assembly by a face gear 31.Alternatively, other types of gear arrangements may be used.

In the preferred embodiment, the reduction gear assembly 27 may beprovided with an encoder system (not shown) to monitor the angularposition of a selected gear in the reduction gear assembly 27. Theangular position of the selected gear provided by the encoder system(not shown) may be used by the control system 81 (FIG. 8) to deriveinformation about the position, velocity, and acceleration of thecartridge access device 36. However, since such encoder systems arewell-known in the art and could be easily provided by persons havingordinary skill in the art after having become familiar with theteachings of the present invention, the particular encoder systemutilized in the preferred embodiment of the present invention will notbe described in further detail.

The reduction gear assembly 27 may comprise any of a wide variety ofgear reduction systems, such as spur gear reduction systems, well-knownin the art. Alternatively, a worm gear reduction system (not shown)could also be used. The motor 25 may comprise a permanent magnet d.c.motor, such as type RS-385PH, available from Mabuchi Motor Corp. ofChina. Alternatively, other types of motors may be provided. Thecharacteristics of the particular type of motor that is selected willdetermine the reduction ratio that is provided by the reduction gearassembly 27. As an example, the reduction gear assembly 27 provides areduction ratio of about 12:1 in the preferred embodiment, althoughother reduction ratios may be used.

In an alternative embodiment, other types of actuator systems 42 may beused to move the cartridge access device 36 along the lower and upperguide members or channels 32 and 34. For example, a chain or belt drivearrangement could be used to connect the motor 25 and the cartridgeaccess device 36 to move the cartridge access device 36 along the lowerand upper guide members or channels 32 and 34. In yet anotherarrangement, a wire rope or “cable” and pulley arrangement may be usedto connect the cartridge access device 36 to the motor 25.

As mentioned above, the cartridge storage system 10 may be provided witha control system 81 (FIG. 8) suitable for controlling, among otherthings, the actuator system 42 associated with the cartridge handlingsystem 12. For example, such a control system 81 can operate theactuator system 42 to move the cartridge access device 36 along theU-shaped path 40 (FIG. 1) so that the cartridge access device 36 mayaccess the desired cartridge 14 from either the cartridge storage rackor magazine 16 or the cartridge read/write device 18, as the case maybe.

For example, referring to FIGS. 1, 7 and 8, the computer system 53 maydetermine that a particular cartridge 14 is needed for processing (i.e.,for writing data to or reading data from the particular cartridge 14).The computer system 53 transmits a request for retrieval of theparticular cartridge 14 to the control system 81 within the cartridgeaccess device 36. In this regard, the computer system 53 preferablyincludes an optical communications device 77′ which is designed tocommunicate with the optical communications device 77″ of the computersystem 85 on the cartridge access device 36. The optical communicationsdevices 77′ and 77″ preferably include any suitable optical transmitterand receiver designed to communicate optical signals. Although othertypes of optical signals are possible, the preferred embodiment of thepresent invention utilizes infrared signals to communicate betweenoptical communications device 77′ and optical communications device 77″.In this regard, there are many commercially available infraredcommunications devices 77′ and 77″ that are suitable for communicatinginfrared signals according to the principles of the present invention.

In order for the optical communications devices 77′ and 77″ to becapable of communication independent of the cartridge access device'slocation along the U-shaped path 40, the cartridge access device 36preferably includes a conical device 211, as depicted by FIGS. 2, 4, 10,and 12. The conical device 211 is preferably comprised of a materialthat reflects optical light. Furthermore, the conical device 211 ispreferably positioned so that the conical device 211 remains within viewof the optical device 77′ as the cartridge access device 36 moves aroundthe U-shaped path 40. Therefore, in the preferred embodiment, theconical device 211 is positioned on a lower surface of the cartridgeaccess device 36, as depicted by FIG. 4. However, the conical device 211may be located in other positions relative to the cartridge accessdevice 36 without departing from the principles of the presentinvention. Since the conical device 211 is comprised of a reflectivematerial and since the conical device 211 is in view of the opticalcommunications device 77′ regardless of the cartridge access device'sposition along the U-shaped path 40, the conical device 211 is designedto reflect each optical signal transmitted from the opticalcommunications device 77′.

In addition, the optical communications device 77″ is preferablypositioned adjacent to (i.e., directly above) the tip of the conicaldevice 211, as depicted by FIG. 12. The slope of the sides of theconical device 211 directly facing the optical communications device 77′are configured to reflect the light transmitted from the opticalcommunications device 77′ into the receiver portion of opticalcommunications device 77″, as depicted by FIG. 13. As the cartridgeaccess device 36 moves around the U-shaped path 40, different sides ofthe conical device 21 la directly face the optical communications device77′ and reflect light into the receiver portion of the opticalcommunications device 77″. Therefore, as the cartridge access device 36moves around the U-shaped path 40, each optical signal transmitted fromthe optical communications device 77′ is reflected into the receiverportion of the optical communications device 77″, regardless of thecartridge access device's location on the U-shaped path 40.

It should be noted that in the preferred embodiment the side of theconical device 211 that faces the pinion drive assembly 52 does notdirectly face the optical communications device 77′ at any of thelocations along the U-shaped path 40. Therefore, the side of the conicaldevice 211 that does not directly face the optical communications device77′ at any of the locations along the U-shaped path 40 (i.e., the sidethat faces the pinion device assembly 52 in the preferred embodiment)does not have to be conical, as depicted by FIGS. 12, 14A and 14B.

Furthermore, by being located adjacent to the tip of the conical device211, each optical signal transmitted by the optical communicationsdevice 77″ is reflected by at least each conical side of the conicaldevice 211 that directly faces the optical communications device 77′ atsome point as the cartridge access device 36 moves around the U-shapedpath 40. Therefore, the optical communications device 77′ receives lightfrom each signal transmitted by optical communications device 77″regardless of the cartridge access device's position on the U-shapedpath 40, since at least one side of the conical device 211 is directlyfacing the optical communications device 77′ at each position of thecartridge access device 36 along the U-shaped path 40. As a result,communication between the optical communication devices 77′ and 77″ ismaintained as the cartridge access device 36 moves around the U-shapedpath 40.

When the control system 81 receives the request from the computer system53 to retrieve a cartridge 14, the control system 81 translates therequest through conventional processing techniques to determine whichcartridge 14 should be retrieved. The control system 81 then transmitscontrol signals to actuator system 42. In response to the controlsignals, the actuator system 42 moves the cartridge access device 36along the U-shaped path 40 until the cartridge access end 180 of thecartridge access device 36 is located adjacent the appropriate cartridge14.

For example, if the desired cartridge 14 is stored in one of thecartridge storage racks or magazines 16, then the actuator system 42 inresponse to the control signals transmitted from the control system 81moves the cartridge access device 36 until the cartridge access device36 is directly opposite the selected cartridge 14. The cartridgeengaging device or “picker” (not shown) associated with the cartridgeaccess device 36 then engages the cartridge 14 and draws it into thecartridge access device 36. Once the cartridge 14 has been completelydrawn into the cartridge access device 36, the actuator system 42 inresponse to control signals from the control system 81 actuates thepinion drive assembly 52 as necessary to move the cartridge accessdevice 36 to the desired cartridge read/write device 18. Once properlypositioned.adjacent the desired cartridge read/write device 18, thecartridge picker (not shown) loads the cartridge 14 into the cartridgeread/write device 18. The computer system 53 can be configured to detectthe loading of the desired cartridge in the appropriate cartridgeread/write device 18, and via optical communications devices 77′ and77″, the control system 81 can be configured to transmit a signalindicating that the cartridge 14 has been loaded in the read/writedevice 18. After determining that the appropriate cartridge 14 has beenloaded, the computer system 53 may then read from or write to thecartridge 14 through conventional techniques.

When the cartridge 14 is no longer needed, the computer system 53 viacommunications devices 77′ and 77″ preferably notifies the controlsystem 81 that the cartridge 14 should be removed from the cartridgeread/write device 18. In response, the control system 81 transmitscontrol signals to the actuator system 42 that causes the cartridgeaccess device 36 to move along the U-shaped path 40 to position thecartridge access device 36 opposite the cartridge read/write device 18(assuming that the cartridge access device 36 is not already located inthe appropriate position). Thereafter, the cartridge picker (not shown)retrieves the cartridge 14 from the cartridge read/write device 18. Thecartridge access device 36 then moves along the U-shaped path 40 untilthe cartridge access device 36 is opposite of the appropriate cartridgestorage rack or magazine 16. The picker (not shown) then returns thecartridge 14 to its appropriate location in the cartridge storage racksor magazines 16.

Although, the present invention has been described hereinabove asutilizing optical signals to communicate between the computer system 53and the control system 81, other communication techniques may beutilized without departing from the principles of the present invention.For example, similar to the juke boxes of the prior art, a cable may beattached from the computer system 53 to the computer system 85 locatedon the cartridge access device 36 in order to communicate signalsbetween the two system 53 and 85. However, it is preferable to utilizeoptical communications devices 77′ and 77″ instead of a cable, becauseoptical communication is less likely to interfere with the motion of thecartridge access device 36.

Another type of communication that may be used without interfering withthe motion of the cartridge are high frequency control signalscommunicated through the engaging members 174 and/or 186 mentionedhereinbefore. In this regard, control signals transmitted from thecomputer system 53 are preferably combined with the power signalsupplied by the power track 201 or 203 through techniques known in theart. Therefore, the control signals are preferably superimposed on thepower signal. Power signals are typically low frequency signals (e.g.,below approximately 100 Hertz). Consequently, the power signal can bepassed through a high-pass filter 213 (FIG. 8) designed to filter outthe power signal in order to recover the control signals. The controlsystem 81 then can use the control signals to appropriately control themovement of the cartridge access device 36, as described hereinbefore.Since the control signal communicated between computer systems 53 and 85can be communicated between the power track 201 or 203 and the engagingmember 174 or 186, it is not necessary to attach a control cable to thecartridge access device 36.

It should be noted that the control signals transmitted to the powertrack 201 or 203 should have a high enough frequency for the high-passfilter 213 to filter out the power signal without significantlyattenuating the control signals. Furthermore, it may be possible toprovide the power tracks 201 and 203 with a power signal of a highenough frequency so that the frequency of the control signal can belower than the frequency of the power signal without affecting theability to filter the power signal from the combined signal. In thisregard, the filter 213 should define a low-pass filter.

By providing the cartridge access device 36 with power via the upper andlower engaging members 174 and 186 and by communicating control signalsbetween the computer system 53 and the control system 81 via opticalsignals or via the power signal, the need for coupling a cable (i.e., apower cable or a control cable) to the cartridge access device 36 iseliminated. Therefore, the cartridge access device 36 can move along theU-shaped path 40 (or any other desirable path) more freely and withoutinterference from a power cable or a control cable.

It should be noted that although the present invention has beendescribed hereinabove as communicating control signals for operation ofthe cartridge access device 36 between the optical communicationsdevices 77′ and 77″, other types of signals communicated between devices77′ and 77″ are possible. For example, status signals indicating thestatus of the cartridge access device 36 or other types of data signalsmay be communicated between the optical communications devices 77′ and77″ without departing from the principles of the present invention.

In concluding the detailed description, it should be noted that it willbe obvious to those skilled in the art that many variations andmodifications may be made to the preferred embodiment withoutsubstantially departing from the principles of the present invention.All such variations and modifications are intended to be included hereinwithin the scope of the present invention, as set forth in the followingclaims.

Now, therefore, the following is claimed:
 1. A system for transferringcartridges, comprising: a cartridge access device configured to receivea cartridge and configured to transfer said cartridge to anotherlocation; a conductive brush coupled to said cartridge access device; aframe assembly having a channel and a power track, wherein said powertrack extends through said channel; and a rod coupled to said brush andconfigured to engage said brush with said power track such that saidbrush slides over a surface of said power track as said cartridge accessdevice moves, and such that said brush is guided through said channel.2. The system of claim 1, wherein said system is a data storage systemand said cartridge is a data cartridge.
 3. The system of claim 1,further comprising: a power wire configured to transmit an electricalsignal to said cartridge access device via said brush and said powertrack; and a filter configured to recover a control signal from saidelectrical signal such that a power signal is filtered from saidelectrical signal.
 4. The system of claim 1, wherein said rod is coupledto a spring.
 5. The system of claim 1, wherein said rod is fixedlycoupled to said brush.
 6. A system for transferring cartridges,comprising: means for accessing a cartridge and for transferring saidcartridge to another location, said cartridge access device having aconductive brush for receiving electrical current; means for engagingsaid brush with a conductive member, wherein said engaging meansincludes a spring for generating a force that pushes said brush towardsaid conductive member; and means for sliding said brush over a surfaceof said conductive members as said cartridge access device moves.
 7. Thesystem of claim 6, further comprising a shaft having a hollow region,wherein said engaging means further includes a rod coupled to said brushand said spring, said rod extending through said hollow region, whereinsaid spring is engaged with said shaft.
 8. The system of claim 6,further comprising: means for transmitting an electrical signal to saidcartridge access device via said brush and said conductive member; andmeans for recovering a control signal from said electrical signal,wherein said recovering means includes a means for filtering a powersignal from said electrical signal.
 9. A system for transferringcartridges, comprising: a frame assembly having a surface in a groove; aconductive member extending through said groove; a cartridge accessdevice for receiving a cartridge and moving relative to said frameassembly; an engaging member coupled to said cartridge access device,said engaging member engaged with said surface; and a conductive brushcoupled to said cartridge access device and engaged with said conductivemember of said groove, wherein said conductive brush slides across saidconductive member as said cartridge access device moves relative to saidframe assembly.
 10. The system of claim 9, wherein said system is a datastorage system and said cartridge is a data cartridge.
 11. The system ofclaim 9, further comprising: a control unit for controlling movement ofsaid cartridge access device based on a control signal, said controlunit coupled to and residing on said cartridge access device; and afilter for receiving an electrical signal from said conductive brush andfor recovering said control signal from said electrical signal, saidfilter coupled to and residing on said cartridge access device.
 12. Thesystem of claim 9, further comprising: means for receiving an electricalsignal transmitted from said conductive member to said conductive brush,said receiving means coupled to and residing on said cartridge accessdevice.
 13. A system for transferring cartridges, comprising: a frameassembly having a surface; a conductive member extending across saidsurface of said frame assembly; a cartridge access device for receivinga cartridge and moving relative to said frame assembly; a conductivebrush coupled to said cartridge access device and engaged with saidconductive member; and a spring coupled to said conductive brush,wherein said conductive brush slides across said conductive member assaid cartridge access device moves relative to said frame assembly. 14.The system of claim 13, further comprising: a shaft coupled to saidcartridge access device, said shaft having a hollow region; and a rodcoupled to said brush and to said spring, said rod extending throughsaid hollow region, wherein said spring is engaged with said shaft. 15.A method for transferring cartridges, comprising the steps of: receivinga cartridge in a cartridge access device; moving said cartridge accessdevice relative to a frame assembly, said frame assembly having asurface; engaging a conductive brush with a conductive member extendingacross said surface of said frame assembly, said conductive brushcoupled to said cartridge access device and to a spring; and slidingsaid conductive brush across said conductive member during said movingstep.